text: /* ----------------------------------------------------------------------
   * Project:      CMSIS DSP Library
   * Title:        arm_abs_f16.c
   * Description:  Floating-point vector absolute value
   *
   * $Date:        23 April 2021
   * $Revision:    V1.9.0
   *
   * Target Processor: Cortex-M and Cortex-A cores
   * -------------------------------------------------------------------- */
  /*
   * Copyright (C) 2010-2021 ARM Limited or its affiliates. All rights reserved.
   *
   * SPDX-License-Identifier: Apache-2.0
   *
   * Licensed under the Apache License, Version 2.0 (the License); you may
   * not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   * www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an AS IS BASIS, WITHOUT
   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  #include "dsp/basic_math_functions_f16.h"
  #include <math.h>
  
  /**
    @ingroup groupMath
   */
  
  /**
    @defgroup BasicAbs Vector Absolute Value
  
    Computes the absolute value of a vector on an element-by-element basis.
  
    <pre>
        pDst[n] = abs(pSrc[n]),   0 <= n < blockSize.
    </pre>
  
    The functions support in-place computation allowing the source and
    destination pointers to reference the same memory buffer.
    There are separate functions for floating-point, Q7, Q15, and Q31 data types.
   */
  
  /**
    @addtogroup BasicAbs
    @{
   */
  
  /**
    @brief         Floating-point vector absolute value.
    @param[in]     pSrc       points to the input vector
    @param[out]    pDst       points to the output vector
    @param[in]     blockSize  number of samples in each vector
    @return        none
   */
  
  
  #if defined(ARM_MATH_MVE_FLOAT16) && !defined(ARM_MATH_AUTOVECTORIZE)
  
  #include "arm_helium_utils.h"
  
  void arm_abs_f16(
    const float16_t * pSrc,
          float16_t * pDst,
          uint32_t blockSize)
  {
      uint32_t blkCnt;                               /* Loop counter */
      f16x8_t vec1;
      f16x8_t res;
  
  
      /* Compute 4 outputs at a time */
      blkCnt = blockSize >> 3U;
  
      while (blkCnt > 0U)
      {
          /* C = |A| */
  
          /* Calculate absolute values and then store the results in the destination buffer. */
          vec1 = vld1q(pSrc);
          res = vabsq(vec1);
          vst1q(pDst, res);
  
          /* Increment pointers */
          pSrc += 8;
          pDst += 8;
  
          /* Decrement the loop counter */
          blkCnt--;
      }
  
      /* Tail */
      blkCnt = blockSize & 0x7;
  
  
      if (blkCnt > 0U)
      {
        /* C = |A| */
        mve_pred16_t p0 = vctp16q(blkCnt);
        vec1 = vld1q(pSrc);
        vstrhq_p(pDst, vabsq(vec1), p0);
      }
  
  }
  
  #else
  #if defined(ARM_FLOAT16_SUPPORTED)
  void arm_abs_f16(
    const float16_t * pSrc,
          float16_t * pDst,
          uint32_t blockSize)
  {
          uint32_t blkCnt;                               /* Loop counter */
  
  #if defined(ARM_MATH_NEON_FLOAT16) && !defined(ARM_MATH_AUTOVECTORIZE)
      f16x8_t vec1;
      f16x8_t res;
  
      /* Compute 4 outputs at a time */
      blkCnt = blockSize >> 2U;
  
      while (blkCnt > 0U)
      {
          /* C = |A| */
  
      	/* Calculate absolute values and then store the results in the destination buffer. */
          vec1 = vld1q_f16(pSrc);
          res = vabsq_f16(vec1);
          vst1q_f16(pDst, res);
  
          /* Increment pointers */
          pSrc += 4;
          pDst += 4;
  
          /* Decrement the loop counter */
          blkCnt--;
      }
  
      /* Tail */
      blkCnt = blockSize & 0x3;
  
  #else
  #if defined (ARM_MATH_LOOPUNROLL) && !defined(ARM_MATH_AUTOVECTORIZE)
  
    /* Loop unrolling: Compute 4 outputs at a time */
    blkCnt = blockSize >> 2U;
  
    while (blkCnt > 0U)
    {
      /* C = |A| */
  
      /* Calculate absolute and store result in destination buffer. */
      *pDst++ = fabsf(*pSrc++);
  
      *pDst++ = fabsf(*pSrc++);
  
      *pDst++ = fabsf(*pSrc++);
  
      *pDst++ = fabsf(*pSrc++);
  
      /* Decrement loop counter */
      blkCnt--;
    }
  
    /* Loop unrolling: Compute remaining outputs */
    blkCnt = blockSize % 0x4U;
  
  #else
  
    /* Initialize blkCnt with number of samples */
    blkCnt = blockSize;
  
  #endif /* #if defined (ARM_MATH_LOOPUNROLL) */
  #endif /* #if defined(ARM_MATH_NEON) */
  
    while (blkCnt > 0U)
    {
      /* C = |A| */
  
      /* Calculate absolute and store result in destination buffer. */
      *pDst++ = fabsf(*pSrc++);
  
      /* Decrement loop counter */
      blkCnt--;
    }
  
  }
  #endif /* defined(ARM_FLOAT16_SUPPORTED */
  #endif /* defined(ARM_MATH_MVEF) && !defined(ARM_MATH_AUTOVECTORIZE) */
  /**
    @} end of BasicAbs group
   */
  